Light emitting diode with improved heat dissipation

ABSTRACT

An improved light emitting diode, comprises a frame, a chip, a wire solder, and sealing compound. The frame is integrally made of conductive metal sheet and provides two sets of connecting pins with two connecting pins for each set. A middle connection is vertically joined to two connecting pins in one set thereof and a plate connection is vertically joined to two connecting pins in the other set thereof. A recess cup is formed at the middle part of the plate connection near the middle connection. The chip is placed and located in said recess cup. The wire solder is made of conductive metal wire and an end thereof is joined to the chip and the other end thereof is joined to the middle connection. The sealing compound covers the chip, the wire solder, part of the plate connection and part of the middle connection and forms a light head on top of the chip. It is characterized in that the plate connection has a width greater than that of said connecting pins, a lower portion of the plate connection and a lower portion of the middle connection exposing outside the sealing compound for a better dissipation of heat. Furthermore, a light emitting diode with a support is provided and the support contacting with the circuit board can reach a better heat dissipation.

BACKGROUND OF THE INVENTION

[0001] 1. Field of The Invention

[0002] The present invention relates to an improved light emittingdiode, and particularly to a light emitting diode, which provides a basewith a bottom part thereof free from sealing and exposing outside for abetter heat dissipation.

[0003] 2. Description of Related Art

[0004] A light emitting diode has been used as an effective light sourcefor years. The light emitting diode provides advantages such as a longerlife span, a higher lightness and lower power consumption such that itis widely applied in a signaling light, a brake light on a car, aChristmas decorative light, and etc.. In addition, the light emittingdiode can provides an effect of instant flash by way of circuit designas desired. Therefore, the light emitting diode is popularly used andthere is a tendency for the light emitting diode to replace theconventional tungsten lamp.

[0005] As shown in FIG. 1, a typical light emitting diode provides atleast two connecting pins “A” as a positive pole and a negative polerespectively. A base “B” is disposed above one of the poles at a lateralside thereof to receive a crystal chip “C” and a brazed wire connects anodal plate “E” extended from the other pole to constitute a circuit.The above said pins “A”, base “B”, nodal plate “E” are made ofconductive sheet metal, and, in practice, are produced by way ofintegrally punch pressing a strip of conductive sheet metal.

[0006] As shown in FIG. 2, a blank sheet used for a prior art lightemitting diode is illustrated. It can be seen that the blank sheet hasbeen punch pressed to form a plurality of blank sections. Each blanksection has connecting pins “A”, the base “B”, and the nodal plate “E”,and the base “B” has a shape of concave inward cone. The restunnecessary parts are cut out as removals.

[0007] As shown in FIG. 3, a bent blank is illustrated. Each connectingpin “A” in the respective blank section is bent into an angle of 90degrees with respect to the base “B” and the nodal plate “E”, and thenthe nodal plate “E” and the chip “C” can be connected with each othervia a brazed wire “D”.

[0008] In order to assure a protection for all parts related to thecircuit, each blank section are insulated by way of sealing compound. Asshown in FIG. 4, a hold fixture is provided with recessions to fit withpattern frames “F”. Each blank section is received in each pattern frame“F” and fits with the pattern frame such that the base “B” and the nodalplate “E” are disposed in the pattern frame. Then, the transparentsealing compound such as epoxy resin is poured into each pattern frame“F” to be flush with the upper surface of the pattern frame “F”. Whenthe poured sealing compound is solidified, the sealed blank sections aretaken out and apart from the pattern frames “F” respectively. Finally,the sealed blank sections are separate into individual light emittingdiodes and each of the light emitting diodes is like the one shown inFIG. 1. As shown in FIG. 1, the base “B” is completely covered by thesealing compound and insulated from the outside and the parts above thebase “B” are in a state of being sealed to insulate from the outsideeither.

[0009] Once the light emitting diode is started in a state of oninstantaneously, an instantaneous current consumption is great so as togenerate a higher temperature in the light emitting diode. When thelight emitting diode is kept “on” for a long period of time, the heatgenerated from both of the chip and the wire solder is unable to releaseoutward and results in a phenomenon of minor flaming. In this way, thedurability of the light emitting diode may be influenced substantially.

[0010] In order to disclose a way overcoming the preceding defects inthe prior art, the inventor has filed at the Chinese Patent Office andhas been assigned Application No. 00107611.6 entitled “Light EmittingDiode and Making Method with Blank Thereof”. (The same invention alsohas been filed as a European Patent Application No. 00111453 and a U.S.patent application Ser. No. 09/582,236 respectively)

SUMMARY OF THE INVENTION

[0011] An object of the present invention is to provide an improvedlight emitting diode, with which the heat generated therein maytransmitted through exposed connecting pins to ease the heatdissipation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention can be more fully understood by referringto the following description and accompanying drawing, in which:

[0013]FIG. 1 is a perspective view of a conventional light emittingdiode;

[0014]FIG. 2 is a fragmentary plan view of a blank of a conventionallight emitting diode after being stamped;

[0015]FIG. 3 is perspective view of a bent blank of a conventional lightemitting diode;

[0016]FIG. 4 is a perspective view of the bent blank shown in FIG. 3 ina process of sealing;

[0017]FIG. 5 is a plan view of a blank sheet of a light emitting diodeaccording to the present invention;

[0018]FIG. 6 is a sectional view of the blank sheet shown in FIG. 5after being bent;

[0019]FIG. 7 is a fragmentary perspective view of the light emittingdiode of the present invention in the process of sealing;

[0020]FIG. 8 is a perspective view of the finished light emitting diodeof the present invention;

[0021]FIG. 9 is a plan view of a blank sheet in a second embodiment ofthe present invention;

[0022]FIG. 10 is a sectional view of the blank sheet shown in FIG. 9after being bent illustrating the bent blank disengaging with a support;

[0023]FIG. 11 is a sectional view similar to FIG. 10 illustrating thebent blank engaging with the support;

[0024]FIG. 12 is a fragmentary perspective view of the light emittingdiode in the second embodiment of the present invention in the processof sealing;

[0025]FIG. 13 is a perspective view of the finished light emitting diodeof the second embodiment of present invention;

[0026]FIG. 14 is a sectional view similar to FIG. 11 illustratinganother support engaging with the bent blank; and

[0027]FIG. 15 is a plan view of a blank sheet similar to that shown inFIG. 9 illustrating connecting pin set for crystal chips in differentcolors.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Referring to FIGS. 5 to 8, the first embodiment of a lightemitting diode according to the present invention basically comprises aframe 1 of a blank sheet, a crystal chip (or a crystal grain) 2, a wiresolder 3, and sealing compound 4.

[0029] The frame 1 as shown in FIG. 5 is made of an elongated conductivesheet metal being continuously formed integrally by way of punch. Fourconnecting pins 11 being constituted in the process of punching aredivided into two sets and one set thereof have a middle connection 12.The middle connection 12 at the central section thereof may have acircular arc but not required. Another set of connecting pins 11 isprovided with a wider plate connection 13 and the middle part of theplate connection 13 is punched a recess cup 14 for placing a chip 2. Asshown in FIG. 6, connecting pins 11 are vertically bent downward atmargins of the middle connection 12 and the plate connection 13respectively.

[0030] The chip 2, which is the prior art, is placed in the recess cup14.

[0031] The wire solder 3 is made of conductive metal wire and joined tothe middle connection 12 and the chip 2 by way of soldering machine toconstitute a closed circuit.

[0032] The sealing compound 4 is made of insulation material and tightlycovers the chip 2, the wire solder 3, part of the plate connection andpart of the middle connection 12 as shown in FIG. 7. Hence, theconnecting pins are left uncovered and exposed outside. In addition, thesealing compound at the top thereof is formed a light head 41 and thelight head 41 may be a shape of semi-ellipse as shown in FIG. 8. But itis not a restriction to have to be the shape of semi0ellipse.

[0033] Referring to FIG. 8 again, the finished light emitting diode ofthe present invention has the upper portions of the middle connection 12and the plate connection 13 sealed by and the lower portions thereofexpose outside for heat dissipation. It can be understood that thetransmission speed of heat is proportional to the transmitted area onwhich the heat may dissipate, that is, the larger transmitted area theplate connection 13 has, the faster speed of heat dissipation can bereach. Because the plate connection 13 has a width greater than that ofthe prior art and the lower portion thereof is exposed outside, asuperior effect of heat dissipation can be obtained substantially.

[0034] Referring to FIGS. 9 to 13, a second embodiment of the presentinvention is illustrated. The light emitting diode in the secondembodiment comprises a frame 5 composed of the blank sheet, a support 6,a crystal chip 7 (or crystal grain), a wire solder 8, and sealingcompound 9.

[0035] The frame 5 of the blank sheet as shown in FIG. 9 is made ofelongated conductive metal being continuously punched integrally to formfour connecting pins 51. These four connecting pins 51 are divided intotwo sets and one set of these connecting pins 51 has a wider middleplate 52. The middle plate 52 at the center thereof is provided with afitting hole 53 and a recess ring 54 is provided to surround the fittinghole 53. As shown in FIG. 10, connecting pins 51 are bent vertically andthe other set of connecting pins 51 is separate from the middle plate 52by way of a cut.

[0036] The support 6 is made of conductive metal and can be hexagon,circle, octagon, and other shapes. The support 6 is composed of asupport base 61 and a support tubing 62 and the support base 61 has abigger size and the support tubing 62 is integrally located at the topof the support base 61. The support tubing 62 has a central hole 621 anda support wall 622 and has an outer diameter corresponding to thefitting hole 53 so as to pass through the fitting hole 53. As shown inFIG. 11, the support engages with the frame 5 by way of riveting, thatis, the support tubing 62 is forced to make the support wall 622 bedeformed and expand outward so as to attached to the recess ring 54tightly. The support wall 622 opens upward to constitute a shape oftrumpet and the lower part of the support tubing 62 constitute a supportbottom 623 for receiving the chip 7.

[0037] The chip 7 is the prior art and placed in and located at thesupport bottom 623.

[0038] The wire solder 8 is made of conductive metal and connects withthe central part of the one set of the connecting pins 51 and the chip 7by way of the soldering machine to constitute a closed circuit.

[0039] The sealing compound 9 is made of insulation material andencloses tightly the chip 7, the wire solder 8, and part of connectingpins 51 to allow connecting pins to expose outside as shown in FIG. 12.As shown in FIGS. 12 and 13, the sealing compound 9 at the top thereofhas a light head 91 extending outward in addition to being an enclosure.The light head 91 may be semi-ellipse but this is not a restriction.Furthermore, the support 6, part of the middle plate 52, and part ofconnecting pins are exposed outside.

[0040] Referring to FIG. 13, the finished light emitting diode in thesecond embodiment exposes the lower portion of connecting pins, part ofthe middle plate 52, the lower portion of support 6. The rest of thefinished light emitting diode is enclosed tightly by the sealingcompound 9. The bottom of support 6 and part of the middle plate exposeoutside for performing dissipation of heat. In addition, once thefinished light emitting diode is inserted to the circuit board, thesupport 6 can contact with the circuit board to carry out the heattransfer for accelerating the dissipation of heat.

[0041] Referring to FIG. 14, another embodiment of the support 6 isillustrated. The support 6 has the support base 61 thereof provide anannular circumference with a hollow part and the annular circumferencecontacts with the circuit board for dissipating the heat.

[0042] Moreover, the engagement of the support 6 and the frame 5 can beby way of gluing, threaded fastening, and etc. in addition to riveting.Because these equivalent engaging ways are the prior art, no detail willbe described further.

[0043] Referring to FIG. 15, the another set of connecting pins 51 nextto the set of connecting pins having the chip 7 is provided with a cutat the middle thereof to connect with chips 7 in different colors. Asshown in FIG. 15, while three crystal grains in three different colorssuch as red, green, and blue or red, yellow, and blue are arranged, thelight emitting diode may display a complete combination of differentcolors. Because this is the prior art, no details will be explainedfurther.

[0044] While the invention has been described with reference topreferred embodiments thereof, it is to be understood that modificationsor variations may be easily made without departing from the spirit ofthis invention, which is defined by the appended claims.

What is claimed is:
 1. An improved light emitting diode, comprising aframe, being integrally made of conductive metal sheet, providing twosets of connecting pins with two connecting pins for each set, a middleconnection vertically joining to said two connecting pins in one of saidtwo sets, a plate connection vertically joining to said two connectingpins in the other one of said two sets, and a recess cup being form at amiddle part of the plate connection near said connection; a chip, beingplaced and located in said recess cup; a wire solder, being made ofconductive metal wire, an end thereof being joined to the chip and theother end thereof being joined to said middle connection; and sealingcompound, covering the chip, the wire solder, part of the plateconnection and part of the middle connection, and being formed a lighthead on top of the chip; characterized in that the plate connection hasa width greater than that of said connecting pins, a lower portion ofthe plate connection and a lower portion of the middle connectionexposing outside the sealing compound for a better dissipation of heat.2. The improved light emitting diode as defined in claim 1, wherein themiddle connection may have a circular arc extending toward the recesscup.
 3. The improved light emitting diode according to claim 1, whereinsaid two connecting pins without loading any chip may be separated toconnect with at least two chips in the recess cup by way of at least twowire solders.
 4. An improved light emitting diode, comprise a frame,being integrally made of conductive metal sheet, providing two sets ofconnecting pins with two connecting pins for each set, said twoconnecting pins in one of said two sets providing a wide middle plate,and the middle plate having a fitting hole; a support, having a supporttubing with a support bottom at an upper end thereof corresponding tothe fitting hole, a support wall of the support tubing being expandingoutward as a shape of trumpet after passing through the fitting hole; achip, being placed at the support bottom after the support tubing beingformed the shape of trumpet; a wire solder, being made of conductivemetal wire, and connecting with said chip and the other set ofconnecting pins respectively; and sealing compound, covering the frameand an upper potion of the support with the chip and the wire solder,and a lower portion of the frame exposing outside.
 5. The improved lightemitting diode according to claim 4, wherein the support has a supportbase below the support tubing.
 6. The improved light emitting diodeaccording to claim 4, wherein the fitting hole may be surrounded aconcentric recess ring for receiving and clamping the expanded supportwall.
 7. The improved light emitting diode according to claim 4, whereinthe engagement between the support and the frame is by way of riveting.8. The improved light emitting diode according to claim 4, wherein thesupport has a round cross section preferably.
 9. The improved lightemitting diode according to claim 4, wherein the sealing compound may beformed a light head.
 10. The improved light emitting diode according toclaim 4, wherein said two connecting pins without loading any chip maybe separated from each other to connect with at least two chips in therecess cup by way of at least two wire solders.